An airway protection program revealed by sweeping genetic control of vagal afferents

Sensory neurons evoke a suite of defensive reflexes to ensure airway integrity. Dysfunction of laryngeal neurons is life-threatening, causing pulmonary aspiration, dysphagia, and choking, yet relevant sensory pathways remain poorly understood. Here, we discover rare throat-innervating neurons (~100 neurons/mouse) that guard the airways against assault. We used genetic tools that broadly cover a vagal/glossopharyngeal sensory neuron atlas to map, ablate, and control specific afferent populations. Optogenetic activation of vagal P2RY1 neurons evokes a coordinated airway defense program- apnea, vocal fold adduction, swallowing, and expiratory reflexes. Selective ablation of vagal P2RY1 neurons eliminates protective responses to laryngeal water and acid challenge. Anatomical mapping revealed numerous terminal morphologies in the larynx, with P2RY1 neurons forming corpuscular endings that appose laryngeal taste buds. Epithelial cells are primary airway sentinels that communicate with second-order P2RY1 neurons through ATP. These findings provide mechanistic insights into airway defense, and a general molecular/genetic roadmap for internal organ sensation by the vagus nerve. Overall design: Single-neuron sequencing of murine vagal sensory ganglia